Landfills are often prolific contributors of greenhouse gases, particularly methane (CH4), which according to the EPA, is a greenhouse gas that is approximately 21 times more potent than carbon dioxide (CO2). As a byproduct of waste disposal and aerobic and anaerobic digestion by microbes of organic matter, landfills produce a variety of gases, including methane and carbon dioxide and others. Some of these gases, typically composed of mostly methane and carbon dioxide, may be collected in compliance with state and federal regulations and combusted in a flare system. However, methane, in particular, may be utilized with contemporary technology to generate electricity by combustion, fuel industrial boilers, or be converted to pipeline quality High-BTU gas so there is inherent value in using methane. In addition to obvious economic advantages derived from using methane as a fuel, flaring methane from the landfill reduces greenhouse gas emissions relative to the situation where methane is neither utilized as a fuel nor flared.
Landfills frequently have gas extraction systems to capture landfill gases. The gases are typically drawn out of a landfill with a low pressure vacuum via a wellfield collection and control system (GCCS). The wellfield typically consists of multiple gas extraction wells that extend deep beneath the surface of the landfill to pull methane from a location near the bottom of the landfill. Each extraction well extends up to the surface of the landfill and is connected with other wells, creating a piping matrix, so that a vacuum can be pulled with one centralized blower or compressor.
Landfill gas extraction wells are perforated along their lengths to allow the gases to be extracted from the waste deposits. There are many factors that influence the effectiveness of a landfill gas extraction well. For example, liquid leachate often flows into the well pipes and there may be a liquid-level blockage that decreases the efficiency of gas extraction. In the instance of a high liquid level, a dewatering pump is often installed in the extraction well to remove the liquid and allow the vacuum to pull on the waste through the perforations again. Such down-well pumps are often used in LFG extraction wells to pump the liquid leachate from the bottom of the well, to the upper end of the well so that it may be disposed. This clears the liquid from the well and increases gas extraction efficiency.
A de-watering pump typically is attached to a lowering cable and includes an outflow pipe through which leachate is pumped out of the well. The pump is typically inserted into the well through the open, exposed end and is lowered with the lowering cable to the desired level by hand, using a lowering cable that is attached to the pump. Removal of the pump after the well has been de-watered is just the opposite: an operator pulls the pump out of the well by hand. But pulling a down-well de-watering pump from the well can be a difficult and time-consuming process. Not only is hand-pulling a pump out of a well an inefficient way to get a down-well pump into and out of a well pipe, but it can be dangerous (for instance, if the pump is dropped into the well in an uncontrolled manner), the process is slow (hand insertion and extraction is inefficient) and can lead to worker injuries. There is a need therefore for improved apparatus for lowering down-well pumps into LFG extraction wells, and extracting the pumps after de-watering is complete.